Search PubMed⌕ Search

Biomedical subjects

M D Brown

Publications and source records attributed to M D Brown.

At least 271 records · Page 15Linked to original sources
PubMed1983

Degenerative spondylolisthesis.

This is an interesting group of patients who have in common the roentgenographic finding of degenerative spondylolisthesis. This is a retrospective, uncontrolled review. It would be interesting to have a similar matched group of 132 patients in the same age group without degenerative spondylolisthesis but with marked degenerative changes to compare symptoms, signs, and outcome of treatment. We have not had adequate follow-up on the nonoperative patients and therefore cannot provide data for comparison with the operative group. A total of 51 of our 132 patients had 83 operative procedures. Twenty-five percent, or 13 patients, showed a degenerative spondylolisthesis at L4-5 with a previous history of having undergone a disk excision at the same level. Seven of the 51 patients (14%) developed a progressive slip following surgery. None of these patients had previous fusion. Two patients of the 17 that we operated on primarily (12%) subsequently developed a progressive symptomatic slip. We have concluded from this review that spinal fusion should be performed in conjunction with decompression more frequently in patients with degenerative spondylolisthesis despite the fact that the majority of these patients are over 60 years of age.

Female↗
PubMed1981

The effect of fluoridation on the dental health of urban Scottish Schoolchildren.

A comparison was made of the dental health of children aged 4-5 and 9-10 in two Scottish towns, one with fluoridated drinking water and the other without. Striking differences were observed. A 44% reduction in decayed, missing, and filled deciduous teeth was found in 4-5 year-olds in the fluoridated compared with the non-fluoridated town and a 50% reduction in decayed, missing, and filled permanent teeth was recorded for the 9-10-year-olds. Larger percentage differences were found for the anterior teeth: a 65% reduction in deciduous incisors and canines, and an 81% reduction in permanent incisors and canines. Fluoridation of public water supplies in urban areas of Scotland would be a safe and effective way of dramatically improving dental health.

Child↗
PubMed1978

An ultrastructural study of regeneration of minced smooth muscle in the vas deferens of the guinea-pig.

Electron microscopic studies were made of the regeneration of minced smooth muscle of the vas deferens of the guinea-pig 3 days to 15 weeks after operation. At 3--5 days the mince contained degenerating smooth muscle cells and dedifferentiating cells showing characteristics of embryonic smooth muscle cells: numerous free ribosomes, well developed rough endoplasmic reticulum and Golgi apparatus with few peripherally placed myofilaments associated with dense bodies. During the first two weeks of regeneration, scattered cells surrounded by debris and collagen were separated by a large extra-cellular space. After three weeks, extracellular space was reduced to near normal values. Regenerating cells had a shorter length than normal cells, but during later stages of regeneration they showed an increase in diameter. Muscle effector bundles began to form after 2 to 3 weeks. Initially there were large gaps between the muscle cells, but at later stages of bundle formation, the extracellular space between the muscle cells was much reduced. From 3 weeks, arterioles appeared between the smooth muscle bundles in the regenerating areas. Regeneration of individual smooth muscle cells was complete by 15 weeks after the operation.

Animals↗
PubMed1976

The effects of different patterns of muscle activity on capillary density, mechanical properties and structure of slow and fast rabbit muscles.

When rabbit fast muscles were chronically stimulated at a frequency naturally occurring in nerves to slow muscles (10 Hz), there was a transformation towards a slow muscle type such as an increase of capillary density, increased activity of the oxidative enzyme, succinic dehydrogenase, and a decrease of muscle fibre diameters. After 28 days the intensity and distribution of SDH and the capillary density were similar to those of soleus. The increases in capillary density preceded the changes in activity of SDH; there was a significantly greater capillary/muscle fibre ratio and number of capillaries/mm2 in muscles stimulated for only 4 days at which time no change could be detected in SDH. These changes were induced by slow frequency stimulation only, and not by an overall increase of activity. Stimulation of fast muscles for 4 days at a higher frequency naturally occurring in the nerves to fast muscles (short bursts of tetani), with the same total number of stimuli as that used in slow frequency stimulation did not produce any changes in capillary density, activity of SDH or contraction times. No changes were observed in either fast or slow muscles stimulated with short bursts of tetani (and lower total number of impulses) up to 28 days. Activation of fast muscles at 5 Hz continuously or 10 Hz intermittently also caused an increase in capillary density. It is therefore concluded that only low frequency activation of fast muscles brings about a transformation of the muscle fibres towards a slow type and that the first noticeable change is an increase in the capillary density.

Animals↗
PubMed1976

A roentgenographic evaluation of frozen allografts versus autografts in anterior cervical spine fusions.

Serial roengenograms of 53 patients who had 76 cervical interspaces grafted with frozen, bone marrrow-free cadaver bone were compared to those obtained from 45 patients who received 63 iliac crest autografts for anterior cervical spine fusion. The roentgenograms were evaluated on the basis of achieving union, delayed union, non-union, and the presence of graft collapse and extrusion. No significant difference was noted in the union rate, with allografts (94%) or with autografts (97%). In 21 patients a higher rate of graft collapse was noted with allografts as compared to autografts in multilevel fusions. In these patients, allograft rejection or the biomechanical properties of the allograft may have contributed to a difference in the rate of graft collapse with cadaver bone. No difference in collapse rate was noted between allografts and autografts in 32 patients with single level fusions. Insertion of frozen bone allografts into intervertebral spaces of the cervical spine has not produced adverse reactions.

Bone Transplantation↗